In wireless communication, a frequency deviation (or offset) occurs between a transmitting apparatus and a receiving apparatus, due to an error (or offset) between clock frequencies used in the transmitting apparatus and the receiving apparatus. The receiving apparatus may estimate the frequency deviation and eliminate effects of the frequency deviation, in order to reduce a bit error rate.
In an OFDM (Orthogonal Frequency Division Multiplexing) reception signal in which a plurality of pilot signals are arranged distributively, the frequency deviation may be estimated by computing a phase rotation from a channel frequency response of each pilot signal and a correlation value of the channel frequency responses among the pilot signals, as proposed in a Japanese Laid-Open Patent Publication No. 2009-124301, for example.
Recently, wireless communication systems such as the LTE (Long Term Evolution) system are being developed. The LTE may realize a highly efficient and highly reliable data transmission, by using the OFDMA (Orthogonal Frequency Division Multiple Access) for the downlink, and using the SC-FDMA (Single Carrier Frequency Division Multiple Access) for the uplink.
In the uplink of the LTE, a control data transmission channel and a user data transmission channel are allocated to different frequency bands. A reference signal for demodulation (or reference signal to be used for demodulation) is included in the control data transmission channel, and a reference signal for demodulation and a reference signal for estimating channel quality are included in the user data transmission channel. Time intervals of the reference signal for demodulation in the user data transmission channel is set to be the same as, or may be set to be longer than time intervals of the reference signal for demodulation in the control data transmission channel. In addition, time intervals of the reference signal for estimating channel quality in the user data transmission channel is set to be longer than the time intervals of the reference signal for demodulation in the user data transmission channel.
Hence, it may be desirable to accurately estimate the frequency deviation also in the wireless communication system in which a plurality of kinds of reference signals having different time intervals are arranged in the control data transmission channel and the user data transmission channel.